# Sweet proteins (brazzein, thaumatin, monellin)
Precision fermentation is scaling up intensely sweet, calorie-free plant proteins as sugar replacements — a US platform's third FDA no-questions letter for brazzein, Europe's first commercial-scale brazzein factory under construction in Lithuania, and an Israeli engineered sweet protein clearing FDA GRAS and Singapore approval with published blood-glucose safety data.
Source: https://en.bioecon.ru/technology/sweet-proteins-brazzein-thaumatin-monellin/
Updated: 2026-08-18
## Overview and value chain
Markers: [EC: FDA GRAS notification / "no questions" letter pathway for novel sweet proteins | OECD: Food systems | Regulator: FDA (USA), EFSA (EU)]
Sweet-protein biotech uses precision fermentation to produce
intensely sweet, calorie-free proteins — brazzein, thaumatin, monellin
and engineered variants — as sugar replacements, moving the category off
its historical reliance on plant extraction. Oobli, based in Davis,
California, describes itself as the first and only commercial-scale
sweet-protein technology platform and received its third FDA "no
questions" letter in September 2025 for its brazzein-based sweetening
ingredient, following that with an Andean regional manufacturing
partnership announced in April 2026 with Magdalena, a sugar producer
diversifying into high-value molecules. In Lithuania, Pentasweet broke
ground in March 2026 on a €65 million ($76 million) precision
fermentation facility in Vilnius — described as Europe's first
commercial-scale sweet-protein factory — with brazzein production
expected to begin in the first half of 2027. In Israel, Amai Proteins'
engineered sweet protein sweelin received FDA GRAS clearance in
February 2026 and Singapore Food Agency approval in May 2026, with
clinical trial results published in the journal Food Chemistry
confirming blood-glucose safety. And in Finland, the VTT Technical
Research Centre engineered Trichoderma reesei fungal strains to express
brazzein at approximately 1.3 g/L in bioreactor culture — several-fold
higher than prior E. coli or yeast systems — estimating a production
cost that could fall to €57–80 per kilogram. Of the catalog's three
named proteins, confirmed live-source activity in this pass concentrates
on brazzein; thaumatin's plant-molecular-farming route is already
covered by a sibling article's Nomad Bioscience entry, and monellin
appears in this pass only in general academic reviews of microbial
sweet-protein expression, without a confirmed dedicated commercial
originator.
The key directions of sweet-protein biotech are:
1. **Precision-fermented brazzein production (Precision-Fermented
Brazzein Production):** yeast or fungal hosts engineered to express
and secrete brazzein at commercial-scale titers, replacing extraction
from the West African oubli fruit.
2. **Engineered next-generation sweet proteins (Engineered
Next-Generation Sweet Proteins):** designed protein variants
optimized for taste profile and stability beyond any single natural
sweet protein.
3. **Regulatory clearance as a market gate (Regulatory Clearance as a
Market Gate):** FDA "no questions"/GRAS letters and country-specific
food-additive approvals functioning as the primary commercialization
bottleneck ahead of scale-up.
4. **High-titer expression-host engineering (High-Titer
Expression-Host Engineering):** strain screening and promoter
optimization (in Komagataella phaffii, Pichia pastoris, Trichoderma
reesei) to raise sweet-protein bioreactor yields and cut production
cost.
### Sectoral value chain
```
[expression-host engineering] ──> [fermentation] ──> [protein purification] ──> [regulatory clearance]
│
(taste/stability
validation)
│
▼
[food/beverage formulation & sale] <─── [ingredient formulation] <─────────────────┘
```
### Value chain levels
| Level | Description | Key inputs/outputs |
|:---|:---|:---|
| **Expression-Host Engineering** | engineering a yeast or fungal host strain to express and secrete a sweet protein | **In:** host organism, sweet-protein gene sequence.
**Out:** engineered production strain. |
| **Fermentation** | culturing the engineered strain in a bioreactor to produce the sweet protein | **In:** engineered strain, growth medium.
**Out:** fermentation broth containing sweet protein. |
| **Protein Purification** | isolating and purifying the sweet protein from the fermentation broth | **In:** fermentation broth.
**Out:** purified sweet-protein ingredient. |
| **Regulatory Clearance** | securing FDA no-questions/GRAS status or equivalent food-additive approval | **In:** purified ingredient, safety/taste data.
**Out:** regulatory clearance for food/beverage use. |
| **Ingredient Formulation** | blending the cleared sweet protein into a food/beverage sweetening system | **In:** cleared sweet-protein ingredient.
**Out:** formulated sweetening ingredient. |
| **Food/Beverage Formulation & Sale** | incorporating the formulated ingredient into a finished consumer product | **In:** formulated sweetening ingredient.
**Out:** finished low/no-sugar food or beverage. |
Cross-cutting technologies of the sector:
- **High-titer strain screening (High-Titer Strain Screening):** selection methods (e.g., zeocin-based screening) identifying production clones with elevated sweet-protein yield.
- **Fungal/yeast secretion engineering (Fungal/Yeast Secretion Engineering):** promoter and expression-system choices (synthetic expression systems, native cbh1 promoter) tuned for extracellular sweet-protein secretion.
- **Sweet-protein taste/stability optimization (Sweet-Protein Taste/Stability Optimization):** protein engineering targeting off-notes, heat stability and pH tolerance for food and beverage applications.
---
## US
The US anchors the platform furthest along toward commercial scale, with
a regulatory track record spanning multiple clearances and an
international manufacturing partnership already announced.
### repeated FDA no-questions clearance, brazzein commercialization, Andean manufacturing partnership
- **Oobli:** describes itself as the first and only commercial-scale sweet-protein technology platform; received its third FDA "no questions" letter in September 2025 for its brazzein-based sweetening ingredient, and announced an Andean regional manufacturing partnership in April 2026 with Magdalena, a sugar producer diversifying into high-value molecules.
---
## CN
Public information on a dedicated Chinese sweet-protein biotech
originator was not confirmed with company-specific detail in this pass;
Chinese-language sources describe thaumatin only as a decades-old,
plant-extracted commodity food additive (GB 2760, INS 957) rather than a
fermentation-based biotech originator.
### no confirmed company-specific biotech originator this pass, thaumatin treated as a legacy plant-extracted commodity
- **No confirmed company-specific detail this pass:** the sources returned for this region were industry market-outlook reports and thaumatin supplier/marketplace listings describing plant-extraction production, not a source confirming a specific Chinese sweet-protein fermentation originator.
---
## EU
Europe anchors the field's first commercial-scale fermentation facility,
a second commercially cleared engineered sweet protein, and the
academic strain-engineering research feeding both.
### Europe's first commercial-scale brazzein factory, a second FDA/Singapore-cleared engineered sweet protein, high-titer fungal strain engineering
- **Pentasweet:** broke ground in March 2026 on a €65 million ($76 million) precision fermentation facility in Vilnius, Lithuania, described as Europe's first commercial-scale sweet-protein factory, with brazzein production expected to begin in the first half of 2027.
- **Amai Proteins:** its engineered sweet protein sweelin received FDA GRAS clearance in February 2026 and Singapore Food Agency approval in May 2026, with clinical trial results published in the journal Food Chemistry confirming blood-glucose safety.
- **VTT Technical Research Centre Finland:** engineered Trichoderma reesei fungal strains — comparing a synthetic expression system against the native cbh1 promoter — to express brazzein at approximately 1.3 g/L in bioreactor culture, several-fold higher than prior E. coli or yeast systems, with an estimated production cost of €57–80 per kilogram.
---
## Leading companies and research institutes
| Company / Institute | Country | Key products / platforms | Tech features | Status 2026 |
|:---|:---|:---|:---|:---|
| **Oobli** | 🇺🇸 USA | *Brazzein sweet-protein platform* | 3rd FDA no-questions letter (Sep 2025); Andean manufacturing partnership | Commercial |
| **Pentasweet** | 🇱🇹 Lithuania | *Brazzein precision-fermentation factory* | €65M ($76M) Vilnius facility; ops H1 2027 | Commercial |
| **Amai Proteins** | 🇮🇱 Israel | *sweelin engineered sweet protein* | FDA GRAS (Feb 2026); Singapore SFA approval (May 2026) | Commercial |
| **VTT Technical Research Centre Finland** | 🇫🇮 Finland | *T. reesei brazzein expression system* | ~1.3 g/L bioreactor titer; est. €57–80/kg cost | Research |
---
## Tech stack and innovations
The stack pairs high-titer expression-host engineering with the regulatory clearance work needed to reach food and beverage shelves.
1. **High-titer fungal/yeast expression engineering (High-Titer Fungal/Yeast Expression Engineering):**
- strain screening and promoter selection raise sweet-protein secretion titers well above earlier bacterial or yeast baselines.
- case: VTT's synthetic expression system in Trichoderma reesei reached ~1.3 g/L brazzein in bioreactor culture, several-fold above prior E. coli/yeast results, at an estimated €57–80/kg production cost.
2. **Engineered next-generation sweet-protein design (Engineered Next-Generation Sweet-Protein Design):**
- protein engineering beyond a single natural sequence targets improved taste profile, stability and regulatory-ready safety data.
- case: Amai Proteins' sweelin cleared FDA GRAS and Singapore Food Agency approval, backed by published clinical blood-glucose safety data.
3. **Regulatory-clearance-gated commercial scale-up (Regulatory-Clearance-Gated Commercial Scale-Up):**
- repeated regulatory clearances de-risk investment in dedicated commercial-scale fermentation capacity.
- case: Oobli's third FDA no-questions letter preceded its Andean manufacturing partnership; Pentasweet's Vilnius facility represents Europe's first commercial-scale build-out for the category.
---
## Value chains and production pipelines
### Industrial pipeline of precision-fermented sweet-protein production (FDA GRAS/no-questions framework)
```
┌───────────────────────────┐ ┌───────────────────────────┐
│ 1. Expression-host eng. │ ───> │ 2. Fermentation │
└───────────────────────────┘ └───────────────────────────┘
│
▼
┌───────────────────────────┐ ┌───────────────────────────┐
│ 4. Regulatory clearance │ <─── │ 3. Protein purification │
└───────────────────────────┘ └───────────────────────────┘
│
▼
┌───────────────────────────┐ ┌───────────────────────────┐
│ 5. Ingredient formulation │ ───> │ 6. Food/beverage sale │
└───────────────────────────┘ └───────────────────────────┘
```
#### Stage 1: Expression-host engineering
A yeast or fungal host strain is engineered, via promoter selection and strain screening, to express and secrete the target sweet protein at high titer.
#### Stage 2: Fermentation
The engineered strain is cultured in a bioreactor, producing sweet protein in the fermentation broth.
#### Stage 3: Protein purification
The sweet protein is isolated and purified from the fermentation broth to food-grade ingredient specification.
#### Stage 4: Regulatory clearance
The purified ingredient's safety and taste data support an FDA no-questions/GRAS determination or equivalent food-additive approval elsewhere.
#### Stage 5: Ingredient formulation
The cleared sweet protein is blended into a sweetening system tuned for a specific food or beverage application.
#### Stage 6: Food/beverage sale
The formulated ingredient reaches finished consumer products as a calorie-free sugar replacement.